1. Field of the Invention
The present invention relates to insectproofing fibers having a durable, excellent insectproofing performance against bugs, and it also relates to a method for preparing the insectproofing fibers.
2. Discussion of Background
Heretofore, it has been known that an insectproofing agent is applied onto fibers or fiber products to give an insectproofing performance to clothes and beddings. However, in the case that the application of the agent was achieved at a fiber processing step, the insectproofing agent is often fallen off the fibers during use, particularly during washing. Specifically speaking, the insectproofing performance is lost by washing the clothes or the like several times. Thus, the durability of the insectproofing performance was poor in the art.
In order to prevent this falling off, there have been proposed a means in which the morphology of fibers onto which the insectproofing agent is applied is made irregular in section, and another means for utilizing void-full fibers. Additionally, in the fields of commercial fiber articles, for example, in the fields of rugs such as carpets, there have also been proposed a method for introducing the insectproofing agent into a backing agent and another method for applying a quaternary ammonium base-containing organosiloxane onto polyester fibers for a quilt or the like.
Moreover, Japanese Patent Application Laid open Nos. 59-163426 and 60-57117 disclose that after stretching and washing steps in fiber manufacturing steps of acrylic fibers, an emulsion of an insectproofing agent such as an insect repellent or an organic phosphorus type insecticide is applied onto the fibers in a swelling state, followed by a dry heat treatment, whereby the insectproofing agent is contained or fixed in the fibers.
However, the insectproofing effect of the quaternary ammonium base-containing organosiloxane is extremely low, and therefore this agent is required to be used in a high concentration. On the other hand, the falling off of the insectproofing agent cannot be prevented sufficiently by the means in which the morphology of the fiber surface is modified, either. Thus, it was difficult to retain the insectproofing effect for a long period of time.
In the case that the insectproofing agent is mixed with a resin such as a binder and then applied to fibers, the fibers cannot smoothly pass through a spinning step and a knitting step, and a soft feeling of the fibers cannot be kept. In consequence, it is troublesome to use this method to the manufacture of clothes. Particularly, when imparting the insectproofing performance to the fibers in a fiber processing step, it is desirable, from the viewpoint of durability of the performance, to apply or deposit the insectproofing agent onto the surface of fibers. However, when a conventional resin is used as the binder, the insectproofing agent is damaged and fallen off the fibers in the subsequent steps by friction and the like, so that an insectproofing function deteriorates and processing devices tend to be contaminated and damaged with the dropped resin particles.
In addition, in the case of the fibers in which the insectproofing agent in the state of emulsion is only contained in the fibers, the insectproofing performance of the fibers can be maintained to certain extent under such relatively moderate conditions as in washing, but the falling off of the insectproofing agent cannot be prevented sufficiently under such conditions using hot water and steam as in a fiber processing step, particularly in a dyeing step in which various surface active agents as well as an acidic or alkaline treatment agent are also used, with the result that the maintenance of the insectproofing effect is difficult.